In the spring of 1965, within weeks of 3,500 American Marines arriving in Vietnam, a 39-year-old Briton named Larry Burrows began work on a feature for LIFE magazine, chronicling the day-to-day experience of U.S. troops on the ground – and in the air – in the midst of the rapidly widening war. The photographs in this gallery focus on a calamitous March 31, 1965, helicopter mission; Burrows’ “report from Da Nang”, featuring his pictures and his personal account of the harrowing operation, was published two weeks later as a now-famous cover story in the April 16, 1965, issue of LIFE.

Photo: Man your battle stations: The crew chief of helicopter Yankee Papa 13, lance corporal James C. Farley, mans an M-60 machine gun during a mission near Da Nang, Vietnam on March 31, 1965. (Photo by Larry Burrows/Time & Life Pictures)

Stefan Sigmund, 29, from the Transylvanian city of Cluj, attempt to smoke 800 cigarettes through a self designed device in less than five minutes, in central Bucharest Tuesday, January 30, 1996, trying to enter the Guinness Book of Records. It is the last of his several attempts entering the record book which included eating 29 hard boiled eggs in four minutes and leaping into a lake from a height of 41 meters (135 feet) even if the Guinness Book of Records no longer rewards self damaging attempts. (Photo by AP Photo/Stringer)

British troops covered in flames from a petrol bomb thrown during a violent protest by job seekers, who say they were promised employment in the security services, in the southern Iraq city of Basra, March 22, 2004. (Photo by Atef Hassan/Reuters)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)

In this September 4, 1963, file photo, a police officer carries off a demonstrator holding a Confederate flag after a group of demonstrators protested enrollment of two African-Americans at Ramsay High School in Birmingham, Ala. The Confederate battle flag has been removed from South Carolina's Statehouse grounds, in the wake of the massacre of nine African-Americans, including a state senator, at an historic black church in Charleston in June 2015. (Photo by AP Photo)

Ukrainians attend an open military training for civilians on a training range in Kiev, Ukraine, 06 February 2022. According to a survey conducted by the Kiev International Institute of Sociology (KIIS) from December 2021, 50.2 percent of Ukrainians said they would resist in case of a Russian military intervention into their city, town or village. Every third respondent to the poll said they were ready to engage in armed resistance, and 21.7 percent said they were ready to participate in civil resistance actions. (Photo by Sergey Dolzhenko/EPA/EFE/Rex Features/Shutterstock)

Police officers introduce a litter of golden retriever puppies to be trained as police dogs during a ceremony at the National Police Academy in La Paz, Bolivia, Monday, August 16, 2021, the date of the feast day for Saint Roch, considered the patron saint of dogs, among other things. (Photo by Juan Karita/AP Photo)

A young fan watches as Green Bay Packers running back AJ Dillon (28) tries his best to ride her bicycle to training camp on Monday, August 1, 2022, at Ray Nitschke Field in Green Bay, Wis. (Photo by Dan Powers/USA TODAY Sports)